WASHINGTON -- When the racist chant began Wednesday night -- "Send her back! Send her back!" -- President Trump paused to let the white-supremacist anger he had stoked wash over him. George Wallace would have been so proud.

That moment at a Trump campaign rally in North Carolina was the most chilling I've seen in American politics since the days of Wallace and the other diehard segregationists. Egged on by the president of the United States, the crowd was calling for a duly elected member of Congress -- Rep. Ilhan Omar, D-Minn., a black woman born in Somalia -- to be banished from the country because Trump disapproves of her views.

This hideous display followed Trump's weekend call for Omar and three other House Democrats, all of them women of color, to "go back" to the "totally broken and crime-infested places from which they came." All of this is an unmistakable echo of the racist taunts that used to be leveled at minority groups that had the temerity to demand civil rights and the gall to achieve political and economic success -- go back to Africa, go back to Mexico, go back to China.

After the election and reelection of the first African American president, one might have thought we were beyond such ugly, desperate racism. To the contrary, perhaps Barack Obama's tenure surfaced long-buried fear and loathing that made Trump's ascension possible.

We can leave that for the political scientists to figure out in the fullness of time. Right now, we have an emergency to deal with. Trump has decided to seek a second term by making a naked appeal to white racism. I didn't think we'd ever see anything worse than his 2016 campaign, which he launched by slandering Mexican immigrants as drug dealers and rapists. Obviously, I was wrong.

The 2018 midterm election, which saw a Democratic blue wave that flipped control of the House, gave a clear sense of what voters think about the Trump presidency. Despite the lies he frequently tells on Twitter about his approval ratings, they have never reached 50%. Trump has to know his reelection bid is in trouble, and he is already in what looks like panic mode.

He has never made a serious effort to expand his base. Instead, he seeks to inflame it.

Trump no longer pretends to be the voice of forgotten working-class Americans. He has become the voice of insecure white Americans, whom he encourages to resent foreigners, immigrants and uppity minorities. His border policy -- separating babies from their mothers, putting children in cages -- is the fulfillment of an ugly revenge fantasy. Cruelty isn't an unfortunate byproduct of Trump's crackdown on asylum seekers. It's the whole point.

The president apparently believes he has found a perfect foil in "the Squad" -- the four newly elected members of Congress he told to "go back" to where they came from. Omar is a refugee from civil war in Somalia who became a U.S. citizen in her teens. The others were all born in this country -- Rep. Rashida Tlaib, D-Mich., in Detroit; Rep. Ayanna Pressley, D-Mass., in Cincinnati; and Rep. Alexandria Ocasio-Cortez, D-N.Y., in New York.

But Tlaib is Palestinian-American, Pressley is African American and Ocasio-Cortez is of Puerto Rican heritage. Trump has decided to try to paint four young, progressive women of color as the enemy. Trump's message to his aging, white base is clear: (BEG ITAL)This is the future you should fear. These are the people you should hate.(END ITAL)

The Republican Party goes along meekly as Trump struts around like a dime-store Mussolini. As for Democrats and independents, history teaches us that the way to deal with hateful demagoguery is not to ignore it, not to downplay it, not to hope it somehow exhausts itself, but to confront it. Trump's fomenting of hate has to be called out. It has to be denounced. It has to be resisted.

Democratic presidential candidates need to realize that elaborate policy positions are necessary but not sufficient. Trump is a bully who will push and push and push. The party is unlikely -- and would be unwise -- to nominate someone too timid to push back.

House Speaker Nancy Pelosi, D-Calif., needs to rethink her strategy as well. I know she understands how much is at stake. I know she worries that impeachment may be a trap. But if Trump is going to preside over what amount to white-power rallies, the time for measured restraint is past.

The next 16 months must be a referendum on Trump's weaponized racism. The answer must be a resounding no.